Status de selênio e associações com parâmetros nutricionais e metabólicos em pessoas idosas institucionalizadas da cidade de Natal/RN

Abstract

Chronic inflammation and changes in body composition are consequences of aging resulting in greater susceptibility to age-related diseases. Selenium (Se) is involved in metabolic processes related to muscle mass, lipid and glycemic profile and anti-inflammatory action. The functionality of Se occurs through selenoproteins, among which selenoprotein P (SELENOP) acts in the distribution of this element in tissues and has antioxidant and anti-inflammatory actions. The aim of the study was to evaluate Se status in institutionalized older adults and test associations with anthropometric parameters, metabolic profile and inflammatory markers. This is a cross-sectional study, carried out with 72 older people living in public and private nursing homes (NH) in Natal/RN. Anthropometric measurements comprised body mass index (BMI), calf circumference (CC) and waist circumference (WC). The biomarkers of Se status assessed were dietary Se intake, plasma Se concentration and SELENOP. Fasting blood glucose, glycated hemoglobin (HbA1c), total cholesterol (TC), high-density lipoprotein (HDL-c), low-density lipoprotein (LDLc) and triglycerides (TG) were quantified to analyze the metabolic profile. The proinflammatory biomarkers analyzed were high-sensitivity C-reactive protein (hsCRP), tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6). The association between variables was performed using the Chi-square test or Fisher's Exact test. Correlations between Se status and the analyzed parameters were performed using Pearson (r) or Spearman (ρ) correlation. The participants were mostly female (72%) with a mean age (SD) of 82.76 (8.55). The mean plasma Se and SELENOP concentrations were 93.08 μg/L (26.71) and 31.09 ng/dL (4.83), respectively. Dietary Se intake was 72.66 μg/day (11.89). Participants with plasma Se <100 μg/L showed a significant association with low weight categorized by BMI (p=0.04). Most participants had elevated HbA1c (65.2%) and high concentrations of hs-CRP (98.5%). In turn, those with lower SELENOP concentrations and lower selenium intake had high HbA1c values (≥6.4%) (p=0.05). Plasma Se showed a positive correlation with BMI (ρ = 0.408, p = 0.001), CC (ρ = 0.270, p = 0.035) and WC (ρ = 0.357, p = 0.005). A positive correlation was observed between Se intake and BMI (r = 0.382, p = 0.004) and WC (r = 0.380, p = 0.004). In conclusion, insufficient Se concentration in plasma was associated with low weight, as well as low SELENOP values and low Se intake with high HbA1c in institutionalized older people in the city of Natal/RN.